Cold Start Of The Plant - Siemens RWF40 Series User Manual

Compact universal controller
Hide thumbs Also See for RWF40 Series:
Table of Contents

Advertisement

5.7 Cold start of the plant

Example
28/56
When a heating system is switched off for a longer period of time, the actual value will
fall.
To achieve a faster control response, the controller starts immediately in high-fire
operation as soon as the control deviation (x-w) has dropped below a certain limit value.
This limit is calculated as follows:
Limit value = 2 * (HYS1-HYS3)
Operating mode: modulating, 3-position output
HYS1 = -3 K
HYS3 = +5 K
w = 60 °C
Limit value = 2 * (-3 - 5) = 2 * (-8) = -16 K
At an actual value below 44 °C, the heating up procedure starts immediately in high-fire
operation, instead of in thermostat mode.
°C
HYS3
W
HYS1
X
7865d20/1099
CC1B7865E
5. Operating modes
February 10, 2000
db
t
Landis & Staefa Division

Hide quick links:

Advertisement

Table of Contents
loading

Table of Contents